Demons have a detailed entry and description in the Marvel Universe Deluxe Edition #3.

The page will feature descriptions or links to some of ones not featured in other "handbooks." I'll have to catch up with and complete this later. I had so much trouble getting the website actually up and running that I skipped entering all of these around the letter "D."

To get a good background on the different types of demons, you should check out the clarifications for the Elder Gods.